Firefox only currently supports DHE with SHA1. Are they going add support for SHA256 DHE when they disable SHA1?
To quote Michael Staruch from the above link:
It looked more like attempts to discredit DHE and push everyone into ECC. And I am not so sure if that's best way to protect our privacy, especially with multiple TLS clients supporting only NSA Suite B curves.
Mozilla, we really need DHE to work with SHA256 and GCM. Sure, fallback to something else (with a second connection, if necessary) if weak dhparams are used by the server.